if the poster's original question hasn't been answered, here it is...maybe
Memory...you match up the memory you're going to buy with the mobo you are targeting.
So you pick a CPU, pick the best mobo for you, then whatever RAM it supports you pick that. It's all clearly labeled...your only problem is getting confused by others convincing you their way is your way.
IF you'll be overclocking yourself, that's where you may want to focus on ram stepping/timing, otherwise you won't need to.
I'm sure the $200 was an avg, if A is $200, B is $50, then C can be $350...ad nauseam
Active budgetting and allocation
Toms hardware, always a good place for tech info